<?php
echo sqrt(9), "\n"; //开平方
echo cos(60*pi()/180), "\n"; //余弦，参数的单位是弧度
echo cos(deg2rad(60)), "\n"; //角度转换为弧度
echo pow(3,2), "\n";  //3的平方
echo round(3.1415926,1),"\n"; //保留一位小数
 echo round(3.1415926,3),"\n"; //保留三位小数

//echo "已知三角形的边角边，计算对边\n";
//echo "请输入三角形的边角边，各数据间用逗号隔开: \n";
//$count=fscanf(STDIN,"%f ,%f ,%f %s",$a,$beta,$b,$others);
////echo "count=$count,a=$a,b=$b,beta=$beta,others=%others\n"
//if($count>3){
//    echo "输入的数据后边不要加多余的乱七八糟的东西~\n\n";
//}else if($count<3){
//    echo "数据输入有误，请根据提示按格式输入数据~\n";
//}else {
//    $c = round(sqrt($a * $a + pow($b, 2) - 2 * $a * $b * cos($beta * pi() / 180)), 2);
//    echo "三角形对边的长度=$c\n";
//
//}

